close all;
clear all;
clc;

%define grid
Sx=1;  %physical size along x
Sy=1;  %physical size along y
Nx=20; %number of cells along x
Ny=20; %number of cells along x


% grid arrays
dx = Sx/Nx;
xa =[0:Nx-1]*dx;
xa = xa - mean(xa);

dy = Sy/Ny;
ya = [0:Ny-1]*dy;
ya = ya - mean(ya);


% create circule
xc = -0.15;
yc = +0.25;
rx = 0.4;
ry = 0.2;
[Y,X] = meshgrid(ya,xa);

A = (((X-xc)/rx).^2 + ((Y-yc)/ry).^2) <= 1;
A'



